Officers said the boy was swimming with other youngsters in the Mudginberri billabong in Kakadu National Park when the crocodile moved in on them.Another boy, also aged 12, was bitten on the arm and had to receive treatment at a medical centre in his remote community, but the second boy disappeared.His friends said they believed the crocodile had grabbed him. Police and park rangers later put out in boats for look for the missing boy.Saltwater crocodiles - referred to locally as 'salties' - are in abundance in the national park, where filming for the original Crocodile Dundee movie was made.Early today Deputy Police Superintendent Sachin Sharma told the Northern Territory News that police and park rangers were on their way to the location, some 140 miles east of Darwin.A billabong - an Aboriginal word - describes a calm, isolated stretch of water left behind when a river changes its course. 'I can confirm there has been a report (of a young boy being taken by a crocodile),' he said.'Police have just arrived, but it's outside the communication zone.'Miss Margot Marshall, a spokeswoman for Parks Australia, confirmed that rangers had joined police in the search for the missing boy.The feared tragedy has occurred when the rest of the country was celebrating Australia Day, commemorating the time when the First Fleet, bringing pioneers - and prisoners - arrived on the continent on January 26, 1788.Signs have been erected near many rivers and pools in the Northern Territory warning people not to enter the water because of the large numbers of crocodiles. Thirteen people, including six children, have been killed by crocodiles in Australia in the past 12 years.(dailymail.co.uk)ANN.Az